Tenacity
-
-
Solubility
-
Insoluble in acids
Durability
-
-
Specific Gravity
3.26-3.364.20-4.30
1
7.18
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Fracture
Conchoidal
Uneven, Conchoidal
Cleavage
Good on {100}
{110} good, 100 moderate, parting on {092} and {011}
Mohs Hardness
6.5-76-6.5
2
10
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Chemical Composition
(Ca,Fe,Mn,Mg) 3Al 2BSi 4O 15(OH)Walter Schumann , Gemstones of the world (2001) More from other references
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006)